ICS9147-12 Datasheet, PDF (1/9 Pages) Integrated Circuit Systems – Pentium/ProTM System and Cyrix™ Clock Chip

Integrated
Circuit
Systems, Inc.
ICS9147-12
Pentium/Pro^TM System and Cyrix™ Clock Chip
General Description
The ICS9147-12 is a Clock Synthesizer chip for Pentium and
PentiumPro plus Cyrix CPU based Desktop/Notebook systems
that will provide all necessary clock timing.
Features include four CPU, seven PCI and eight SDRAM
clocks. Three reference outputs are available equal to the
crystal frequency, plus the IOAPIC output powered byVDDL.
Additionally, the device meets the Pentium power-up
stabilization, which requires that CPU and PCI clocks be stable
within 2ms after power-up.
High drive PCICLK and SDRAM outputs typically provide
greater than 1V/ns slew rate into 30 pF loads. CPUCLK outputs
typically provide better than 1V/ns slew rate into 20 pF loads
while maintaining 50±5% duty cycle. The REF clock outputs
typically provide better than 0.5V/ns slew rates.
The ICS9147-12 accepts a 14.318MHz reference crystal or
clock as its input and runs on a 3.3V supply.
Features
• Generates system clocks for CPU, IOAPIC, SDRAM,
PCI, plus 14.318 MHz REF(0:2), USB, Plus Super I/O
• Supports single or dual processor systems
• Supports Intel 60, 66.8MHz, Cyrix 55, 75MHz plus 83.3
and 68MHz (Turbo of 66.6) speeds.
• Synchronous clocks skew matched to 250ps window on
CPU, SDRAM and 500ps window on PCI clocks
• CPU clocks to PCI clocks skew 1-4ns (CPU early)
• Two fixed outputs, 48MHz and 24 MHz
• Separate 2.5V and 3.3V supply pins
- 2.5V or 3.3V output: CPU, IOAPIC
- 3.3V outputs: SDRAM, PCI, REF, 48/24 MHz
• No power supply sequence requirements
• 48 pin 300 mil SSOP
Pin Configuration
Block Diagram
9147-12 Rev A 072597P
48-Pin SSOP
Power Groups
VDD1 = REF (0:2), X1, X2
VDD2 = PCICLK_F, PCICLK (0:5)
VDD3 = SDRAM (0:7),
VDD4 = 48MHz, 24MHz
VDDL = IOAPIC, CPUCLK (0:3)
Pentium is a trademark on Intel Corporation.
ICS reserves the right to make changes in the device data identified in this
publication without further notice. ICS advises its customers to obtain the latest
version of all device data to verify that any information being relied upon by the
customer is current and accurate.